|
|
Synchrotron radiation allows a multitude of physical-chemical methods which are important for geoscientific problems.
This includes the analysis of trace elements in minerals and rocks with high accuracy and spatial resolution (SXRF).
For phase analysis and for looking at the geometric arrangement of atoms, ions and molecules in minerals, scattering methods are used
(single crystal and powder diffractometry). The conditions in the Earth's interior can only be studied by experiments. High pressure
crystallography with synchrotron radiation has therefore provided great contributions in mineralogy (pressure cells, energy dispersive
synchrotron radiation). Spectroscopic methods are used to study chemical bonding in minerals and crystals, but also for solving structural
problems or to determine cation distributions (XAS, XAFS/EXAFS, XANES, IRS).
Source: Physikalisch-chemische Untersuchungsmethoden in den Geowissenschaften, 2001
More on the topic:
|
|
Pressemitteilung der ESRF (30.07.2012)
Scientists have recreated the extreme conditions at the boundary between Earth's core and its mantle, 2,900 km beneath the surface. Using the world's most brilliant beam of X-rays, they probed speck-sized samples of rock at very high te
mperature and pressure to show for the first time that partially molten rock under these conditions is buoyant and should segregate towards the Earth's surface. This observation is a strong evidence for the theory that volcanic hotspots like the Hawaiian Islands originate from mantle plumes generated at the Earth's core-mantle boundary. The results are published in Nature dated 19 July 2012.
[mehr]
|
|
|
|
BESSY Annual Report 2003
Water plays an important role in geodynamic processes in the Earth's upper mantle. Beside in nominally
hydrous minerals such as amphibole, serpentine, mica nd talc hydrogen may be stored in nominally
anhydrous minerals (NAMs) such as pyroxene, garnet and olivine. NAMs can dissolve traces of OH as point defects.
Although the amount of water in these minerals is genearlly very low (up to 0.1 wt % H2O), the
water content that can be dissolved in NAMs in the upper mantle is large and may exceed the amount of water
in the hydrosphere. Traces of water in minerals can be detected by IR spectroscopy.
[more]
|
|
|
|
BESSY Annual Report 2005
To investigate fracture propagation in hard rocks in response to applied loads it is essential to
know the existence and orientation of pre-existent microcracks. Because nucleation, growth
and interaction of microcracks are considered to be the dominant, controlling mechanisms of
macroscopic failure. Nevertheless, grain boundaries, low-aspect ratio cavities or interfaces of
two different minerals can also function as stress concentrators and be responsible for crack
initiation. Synchrotron tomography at
BESSY provides the possibility to investigate microscopic features of natural rock samples.
[more]
|
|
|
|
print version
